ASL sign for: bam (exclamation)

Definition: An exclamation imitating the sound or vibration of a hard blow.

This video shows you a couple of examples of some more variants, depending on the complex structure of a sentence involving a classifier predicate and a subject/object. But, the mouth morpheme is usually "bam".

If one feels or hears a hard blow of something unknown, then the first sign in the video is used.